Downhole surge reduction method and apparatus

ABSTRACT

A method and apparatus for use in the oil well industry for running in drilling/production liners and sub-sea casings down a borehole through drilling fluid on a drill pipe using a multifunction diverter tool with the benefits of surge pressure reduction are disclosed. In accordance with the present invention, a multi-function diverter tool includes a housing assembly with a set of flow holes formed therein and a sliding sleeve arranged within the housing assembly having two sets of flow ports formed therein at different axial locations along the sleeve. By aligning either set of flow ports of the sleeve with the flow holes of the housing, the tool is set in a “surge pressure reduction” mode. By shifting, or axially indexing, the sleeve downward, the set of flow holes becomes blocked by the sleeve thus setting the tool in a “circulation” or “cementing” mode. This shifting or indexing is accomplished using an indexing mechanism. The multi-function diverter tool of the present invention can be shifted from a first “surge pressure reduction” mode to a “circulation mode,” from the “circulation mode” to a second “surge pressure reduction” mode, and finally from the second “surge pressure reduction” mode to a “cementing” mode. The indexing mechanism of the present invention includes a return spring and brake system which provides the tool with more reliable shifting functionality.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation-in-part of U.S. patent application Ser. No. 09/812,522 filed Mar. 20, 2001 which claims the benefit of the filing date of Provisional application Ser. No. 60/255,481 filed Dec. 14, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a method and apparatus for use in the oil well industry, and, more particularly, to a method and apparatus for providing surge reduction functionality while running a drilling/production liner or sub-sea casing downhole.

[0004] 2. Description of the Prior Art

[0005] The principle of operation of a surge reduction tool is described in U.S. Pat. No. 5,960,881 (“the '881 patent”), which is incorporated herein by reference and which should be referred to with respect to the advantages provided by that invention. In practice, the invention of the '881 patent has provided the oil well industry with the long-desired capability of running in drilling/production liners faster and more reliably with a minimum of lost drilling mud.

[0006] While the device of the '881 patent provided for the first time a mechanism for reducing surge pressure, circumstances may be encountered during the running downhole of a drilling/production liner where even a tool in accordance with the '881 patent may be rendered ineffective to reduce surge pressure. Specifically, if a drilling/production liner encounters a tight hole condition or bridge while being lowered into the wellbore, then it is not possible to effectively circulate mud around the end of the drilling/production liner to help free it. This is because the surge pressure reduction flow ports of the apparatus in accordance with the '881 patent are open and will short-circuit flow to the annular space above the drilling/production liner. If this happens, the driller may establish circulation by dropping the drop ball before reaching the target depth to close the open ports of the surge reduction tool. The driller may then use the mud pumps to clean up and wash out the borehole. Once the driller makes this decision, however, he must attempt to lower the drilling/production liner to the target depth without further benefits of surge reduction, since the tool can only be functioned once.

[0007] Accordingly, the oil well industry would find desirable a surge reduction tool that allows an additional sequence of opening and closing of the flow ports to provide alternation between the “surge reduction” and the “circulation” modes of operation. In other words, a tool would be desirable which: (1) initially provides surge reduction, (2) allows for circulation to be established in the event the drilling/production encounters tight hole conditions, and (3) provides surge reduction after the borehole conditions are improved.

[0008] The oil well industry has seen other devices that claim to regulate communication between the wellbore annular space and the well fluid; however, none of these devices provides surge reduction functionality. U.S. Pat. No. 3,457,994, assigned on its face to Schlumberger Technology Corp., discloses a well packer apparatus with a pressure-powered valve and locking latch device which can be initially set between open and closed conditions and lowered into a wellbore on a running-in string. However, the pressure-powered valve is opened and closed by an actuator, not indexed by a drop ball. In addition, the stated purpose of the '944 device is to regulate the passage and removal of the commodity within the well, not to facilitate surge reduction of a downhole tool.

[0009] U.S. Pat. No. 3,517,743, assigned on its face to Dresser Industries, Inc., provides a selective interval packer device which permits fluid to pass through a seated ball valve during descent into a wellbore and which aligns with a selectively indexed location along the wellbore. However, the stated purpose of the device is to isolate and communicate with formations at selected intervals. The opening of the ball valve to permit fluid flow through the packer device and the indexed regions along the wellbore facilitate this purpose and do not provide a means to reduce surge pressure during the running of drilling/production liners.

[0010] U.S. Pat. No. 5,730,222 (“the '222 patent”), assigned on its face to Dowell, provides a downhole circulating sub device to direct or divert fluid flow between a measurement while drilling (MWD) tool and a flow activated motor and drill bit. The sub device is connected between the upper MWD tool and the lower drill bit, and may be activated and deactivated by a respectively pushing or pulling on a coiled tube. When activated, the sub device directs flow to the flow activated motor and drill bit. Once deactivated, the sub device short-circuits the drill, but still allows for flow through the MWD tool (the '222 patent, FIGS. 1 and 2). However, the device of the '222 patent is manipulated by physically pushing or pulling on a coil tube and not by a dropping a ball through drill string and into apparatus to open or close the flow ports. Furthermore, the stated purpose of the device of the '222 patent is to direct fluid flow into or divert fluid flow from a downhole flow activated tool, and not to implement surge pressure reduction.

[0011] Subsequent to the invention of the '881 patent, others have attempted to produce apparatus which provides surge reduction. Baker Hughes began to offer a device which functions in accordance with the '881 patent. Also, in U.S. Pat. No. 6,082,459 (“the '459 patent”), assigned on its face to Halliburton, a diverter apparatus is disclosed for reducing surge pressure while running a drilling/production liner in a partially cased well bore. Halliburton is believed to market this device as the “SuperFill” system. According to the '459 patent and Halliburton's literature, the SuperFill system is movable from a closed port position to an open port position and vice versa.

[0012] The diverter device shown in FIG. 3B of the '459 patent comprises an inner tubular housing, an outer sliding sleeve, and a system of drag springs arranged outside and surrounding the sliding sleeve. In operation, the diverter is run downhole where the springs directly engage a previously cemented drilling/production liner. As the springs engage the drilling/production liner, the drag springs compress and drag the outer sliding sleeve relatively upwards with respect to the inner housing into an open port position. To move the apparatus from the open to the closed position, the '459 patent states that downward movement is stopped and an upward pull is applied so that the tubular housing moves upwardly until the sliding sleeve covers the flow ports in the inner tubular housing. According to the '459 patent, the diverter apparatus includes a J-slot so that the diverter can be locked in the closed position by rotating the drill string.

[0013] In practice, it is believed that substantial problems may be encountered in use of the tool of the '459 patent. For example, one would not want to move the tool of the '459 patent from an open port position to a closed port position without also locking the tool in the closed port position. This is because the weight of the drilling/production liner may cause the tool to trip to the open port position, if not locked. To lock the tool of the '459 patent, it is rotated to the right. This rotation also causes the running tool and drilling/production liner to rotate. If the rotating drilling/production liner gets caught in the borehole, the continued rotation can result in the running tool becoming disengaged from the drilling/production liner. To avoid this disastrous result, the drilling/production liner in practice is set on the bottom of the borehole before the diverter apparatus is locked in the closed position. This result is undesirable, since the drilling/production liner cannot be properly cemented in place under these conditions.

[0014] A tool as described in the '881 patent includes a finger latching apparatus to latch the sliding valving sleeve apparatus into position. When the drilling/production liner has reached target depth, a ball is pumped down the drill string until it lands in a yieldable seat that is contained within the latched valving sleeve. Once the ball has landed in the yieldable seat, pressure is increased until the pressure end load force overcomes the latched spring fingers and allows the valving sleeve to move into a lower position that closes the vent ports. The pressure is then increased further until the seat yields to an extent that allows the ball to pass through the seat and on down to the bottom of the borehole. In the embodiment of the invention of the '881 patent, the release pressure can vary from tool to tool, because the release pressure is primarily controlled by the flexibility of the spring fingers and the friction between the spring fingers and the inner surface of the sleeve.

[0015] U.S. patent application Ser. No. 09/812,522 (“the '522 application”), the parent of the present application, provides a method and apparatus for running a drilling/production liner through drilling fluid down a borehole with an additional mode of surge pressure reduction. The surge reduction tool of the '522 application includes a diverter device having a housing with an axial bore therethrough and a set of flow holes formed therein, a valving sleeve arranged within the housing having two sets of flow ports formed therein, and an indexing mechanism for shifting the valving sleeve axially downward. The valving sleeve is initially arranged such that the first set of flow ports is aligned with the flow holes of the housing to provide surge reduction functionality. This is called the “open port position.” Once the tool is run downhole, the indexing mechanism can be activated to shift the valving sleeve downward such that the set of flow holes of the housing is blocked to facilitate circulation of drilling fluid through the diverter device and to the bottom end of the drilling/production liner. This is called the “closed port position.” Once circulation is accomplished, the indexing apparatus can be activated again to shift the valving sleeve downward into a second open port position such that the second set of flow ports is aligned with the set of flow holes of the housing to reestablish surge reduction functionality. Once the drilling/production liner is run to its target depth, the indexing apparatus can be activated one final time to shift the valving sleeve downward into a second closed port position such that the set of flow holes of the housing is blocked again to facilitate cementing operations.

[0016] As described in the '522 application, the indexing apparatus includes four protruding latching rings formed on the axial bore of the housing at different axial locations and a plurality of alternating long and short latching fingers attached to the sleeve for engaging the latching rings and holding the sleeve in either an open port position or closed port position.

[0017] While the '522 application does provide for a much desired additional sequence of surge reduction functionality, it has been observed that problems may occur during shifting of the tool. More particularly, it has been observed that the short latching fingers of the indexing apparatus sometimes fail to disengage from the protruding latching rings of the housing thereby locking the sleeve in whatever position it is in at the time. If this happens while the tool is in the open port position, then the tool cannot be shifted out of the surge reduction mode and critical cementing operations cannot be accomplished.

[0018] Accordingly, the present invention provides a method and apparatus for running a drilling/production liner through drilling fluid down a borehole with an additional mode of surge pressure reduction having a more reliable indexing mechanism to reduce the risk of shift locking.

SUMMARY OF THE INVENTION

[0019] In accordance with the present invention, a method and apparatus for use in the oil well industry for reducing surge pressure while running a drilling/production liner down a borehole through drilling fluid on a drill pipe is provided.

[0020] The apparatus in accordance with the present invention includes a housing having a top end and a bottom end for connection to a hanger. The housing has an axial bore therethrough and a set of flow holes formed therein. The housing is suspended from the drill pipe, and the drill pipe provides a communication conduit between a drilling rig and the borehole.

[0021] Apparatus in accordance with the present invention further comprises a sleeve within the housing. The sleeve has two sets of flow ports which are located at different axial locations along the sleeve. When either set of sleeve flow ports is aligned with the set of housing flow holes, the apparatus is in an “open port position” thereby providing surge pressure reduction functionality. When the sleeve blocks communication through the set of housing flow holes, the apparatus is in a “closed port position” thereby providing communication between the drilling rig and the bottom of the borehole. Initially, the sleeve is positioned in the housing such that a first open port position exists. Indexing apparatus is provided for axially moving the sleeve from the first open port position to a first closed port position, from the first closed port position to a second open port position, and from the second open port position to a second closed port position.

[0022] In a preferred embodiment of the present invention, the indexing apparatus includes a camming sleeve and spring washers which provide a tool in accordance with the present invention with a more predictable release pressure than has heretofore been available. Furthermore, in a preferred embodiment of the present invention, the indexing apparatus includes an indexing sleeve, an indexing sleeve return spring, and a braking ring which provide the indexing apparatus with more reliable shifting functionality.

[0023] Another feature of the surge reduction tool of the present invention is a dart directing sleeve in the housing which has a smaller, smoother bore than the drill string and provides the important function of aligning a dart before it lands in the seat so that the dart resistance when passing through the seat is minimized.

[0024] Yet another feature of the improved tool of the present invention are molded seals arranged in the housing above and below the vent port which reduces the potential for hydraulic lock and provides a seal mechanism that is more reliable while running in downhole conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the accompanying drawings:

[0026]FIG. 1 is an elevation view of a wellbore depicting a drilling/production liner being run downhole.

[0027]FIG. 2 is a section view of one embodiment of the present invention depicting the entire assembly in the first open port position to facilitate surge reduction.

[0028]FIG. 2A is an enlarged section view of the embodiment of FIG. 2.

[0029]FIG. 2B is an enlarged section view of the embodiment of FIG. 2 depicting the first drop ball landing in the yieldable seat assembly.

[0030]FIG. 2C is an enlarged section view of the embodiment of FIG. 2 depicting the first drop ball being used to compress the springs and shift the indexing mechanism downward into the first closed port position.

[0031]FIG. 2D is an enlarged section view of the embodiment of FIG. 2 depicting the first drop ball being forced through the yieldable drop ball seat and the springs resetting.

[0032]FIG. 3 is a section view of one embodiment of the present invention depicting the entire assembly in the first closed port position to facilitate circulation of drilling fluid.

[0033]FIG. 3A is an enlarged section view of the embodiment of FIG. 3 depicting the second drop ball landing in the yieldable seat assembly.

[0034]FIG. 3B is an enlarged section view of the embodiment of FIG. 3 depicting the second drop ball being used to compress the springs and shift the indexing mechanism downward into the second open port position.

[0035]FIG. 3C is an enlarged section view of the embodiment of FIG. 3 depicting the second drop ball being forced through the yieldable drop ball seat and the springs resetting.

[0036]FIG. 4 is a section view of one embodiment of the present invention depicting the entire assembly in the second open port position to facilitate surge reduction.

[0037]FIG. 4A is an enlarged section view of the embodiment of FIG. 2 depicting the third drop ball landing in the yieldable seat assembly.

[0038]FIG. 4B is an enlarged section view of the embodiment of FIG. 4 depicting the third drop ball being used to compress the springs and shift the indexing mechanism downward into the second closed port position.

[0039]FIG. 4C is an enlarged section view of the embodiment of FIG. 4 depicting the third drop ball being forced through the yieldable drop ball seat and the springs resetting.

[0040]FIG. 5 is a section view of one embodiment of the present invention depicting the entire assembly in the second closed port position to facilitate cementing operations.

[0041]FIG. 6 is an enlarged section view section of an embodiment of the braking ring of the present invention.

[0042]FIG. 7 is an elevation view of a drilling/production liner at final depth of a downhole run.

[0043]FIG. 8 is an elevation view of a drilling/production liner as cement is pumped downward through the drilling/production liner.

[0044]FIG. 9 is an elevation view of a drilling/production liner as cement is forced from the bottom end of the drilling/production liner and upward into annular space between the drilling/production liner and the borehole.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

[0045] In oilfield applications, a “drilling/production liner” and a “sub-sea casing” are tubular members which are run on drill pipe. The term “sub-sea casing” is used with respect to offshore drilling operations, while the term “drilling/production liner” is used with respect to both land and offshore drilling operations. For ease of reference in this specification, the present invention is described with respect to a “drilling/production liner.” However, it should be appreciated that the present invention may also be used for running a sub-sea casing down a borehole. In the appended claims, the term “tubular member” is intended to embrace either a “drilling/production liner” or a “sub-sea casing.” In the specification and appended claims, the term “operatively connected” is used to mean “in direct connection with” or “in connection with via another element,” and the term “set” is used to mean “one or more.”

[0046] A description of certain embodiments of the present invention is provided to facilitate an understanding of the invention. This description is intended to be illustrative and not limiting of the present invention.

[0047] With reference first to FIG. 1, the general components of a system in which a tool in accordance with the present invention is used are illustrated. A mast M suspends a traveling block TB. The traveling block, in turn, supports a top drive TD which moves vertically on a block dolly BD. An influent drilling fluid line L supplies the top drive TD with drilling fluid from a drilling fluid reservoir (not shown). A launching manifold LM connects to a drill string S. The drill string S comprises numerous pipe elements which extend down into the borehole BH, and the number of such pipes is dependent on the depth of the borehole BH. A surge reduction bypass device B in accordance with the present invention is connected between the bottom end of drill string S and the top of hanger 162. A drilling/production liner 161 is suspended from hanger 162. An open guide shoe 165 is fastened to the bottom of the hanger 162.

[0048] Solidified cement CE1 fixes a surface casing SC to the surrounding formation F. The surface casing SC contains an opening O in the uppermost region of the casing adjacent to the top. The opening O controls return of drilling fluid as it travels up the annulus between the drill string S and the surface casing SC.

[0049] Solidified cement CE2 fixes an intermediate casing IC to the surrounding formation F. The intermediate casing IC is hung from the downhole end of the surface casing SC by a mechanical or hydraulic hanger H.

[0050] The drilling/production liner 161 includes a wiper plug 163 and a landing collar 160. The annular space between the drill string S and the intermediate casing IC is greater in area than the annular space between the drilling/production liner 161 and the intermediate casing IC. While the invention is not intended to be limited to use in tight or close clearance drilling/production liner runs, the benefits of the present invention are more pronounced in tight clearance running, since as the area is reduced and the pressure (pressure is equal to weight/area) is increased.

[0051] With reference now to FIGS. 1 and 2, one embodiment of the surge reduction tool B of the present invention includes a housing assembly having an upper housing 101, a middle housing 102, and a lower housing 103 which are operatively connected together to form an axial bore therethrough. The lower end of a top sub 104 is in threaded engagement with the upper housing 101, and the upper end of the top sub is operatively connected to the drill string S. The upper end of a lower sub 105 is in threaded engagement with lower housing 103, and the lower sub is operatively connected to a hanger CH. While the housing assembly described above comprises three connected units—an upper housing, a middle housing, and a lower housing, it will be appreciated that these components may be combined into a single housing unit having an upper section, a middle section, and a lower section.

[0052] With reference to FIG. 2A, an indexing mechanism is contained within the housing assembly. The indexing mechanism has four latching positions 131, 132, 133, 134 designed to support axially downward indexing. An indexing sleeve 200 having an outer diameter smaller than the axial bore of the housing assembly is arranged within the housing assembly. Axially spaced internal protrusions or “rings” at positions 131, 132, 133, 134 are formed on or attached to the inner surface of the indexing sleeve 200. The axial spacing of these rings at positions 131, 132, 133, and 134 determines the specific position of the indexing mechanism at any given time.

[0053] Still with reference to FIG. 2A, one embodiment of the indexing mechanism of the present invention is illustrated. A yieldable seat assembly 110 is installed on a shoulder formed in a camming sleeve 140. The lower end of a dart directing sleeve 109 is installed on top of the yieldable seat assembly 110, and a snap ring 146 is utilized to secure yieldable seat assembly and dart directing sleeve in place on the upper end of a camming sleeve 140. The camming sleeve 140 is supported by spring washers 124. While any suitable spring washers may be used to support the camming sleeve, Belleville spring washers are preferred. The spring washers 124 are, in turn, supported by a threaded sleeve 142 that is operatively connected to a valving sleeve 141.

[0054] With reference to FIGS. 2 and 2A, at least two sets of axially spaced sleeve flow ports 135, 136 are formed in valving sleeve 141. Similarly, a set of housing flow holes 126 are formed in middle housing 102. As explained below, the valving sleeve 141 is indexed axially downward in the operation of a tool in accordance with the present invention. Initially, the axial position of valving sleeve 141 is such that the set of sleeve flow ports 136 is aligned with the set of housing flow holes 126. When the axial position of valving sleeve 141 is such that either set of sleeve flow ports 135, 136 is aligned with the set of housing flow holes 126, an “open port position” is established. When the axial position of valving sleeve 141 is such that no set of sleeve flow ports 135, 136 is aligned with the set of housing flow ports 126, a “closed port position” is established. The terms “open port position” and “closed port position” in the appended claims have the foregoing definitions.

[0055] While the surge reduction tool described above has a housing with one set of housing flow holes and a valving sleeve with two sets of axially spaced sleeve flow ports, it will be appreciated that a tool in accordance with the present invention may comprise a housing with two sets of axially spaced housing flow ports and a valving sleeve with one set of sleeve flow ports.

[0056] An embodiment of a tool in accordance with the present invention also includes an assembly of pivoting latching fingers 114, 115. One end of each latching finger 114, 115 is attached to the threaded sleeve 142. The assembly of latching fingers comprises both long fingers 114 and short fingers 115. The short fingers 115 are evenly interspersed among the long fingers 114 such that every other finger is a short finger. Each latching finger 114, 115 includes an external shoulder that rests on the internal rings of the indexing sleeve 200 while also including an internal protrusion that interacts with the camming sleeve 140 such that the camming sleeve alternately forces the short or long latching fingers radially outward.

[0057] The short and long latching fingers 114, 115 are initially positioned to span across the top internal ring at position 131. The camming sleeve 140 is supported in the uppermost position by the spring washers 124 until a drop ball 127 (FIG. 2B) lands in the yieldable seat 110. With the camming sleeve 140 in the uppermost position, the long latching fingers 114 are forced radially outward and thus the internal ring at position 131 of the indexing sleeve 200 restrains the indexing assembly from moving downward.

[0058] A dart directing sleeve 109 fits in an opening in top sub 104 and functions to center a dart 164 (FIG. 8) on the seat of yieldable seat 110. Furthermore, the diameter of the dart directing sleeve 109 is less than the diameter of the drill pipe P (FIG. 1) which results in the dart being accelerated as it passes through the dart directing sleeve 109. The increased alignment accuracy and descent velocity of the dart within the dart directing sleeve 109 reduces the applied pressure required to yield the seat of yieldable seat assembly 110.

[0059] With reference to FIG. 2, an embodiment of a tool in accordance with the present invention also includes a packing assembly having molded seals 122 in the lower housing 102. The molded seals 122 are arranged in the axial bore of the housing both above and below the set of housing flow holes 126. The molded seal located below housing flow port 126 sits on a spacer seal 128, and has the open position of the molded seal facing downward. The molded seal above the housing flow port 126 has the open portion of the molded seal facing upward.

[0060] With reference to FIGS. 2 and 2A, an embodiment of a tool in accordance with the present invention further includes an indexing sleeve return spring 201 and a spring pusher 202 arranged below the indexing sleeve 200 such that the indexing return spring engages the spring pusher and the spring pusher engages the indexing sleeve.

[0061] With reference to FIG. 6, an embodiment of a tool in accordance with the present invention still further includes a braking ring 203 attached to the bottom end of the valving sleeve 141. The braking ring 203 has an axial bore formed therethrough and includes a brake pad 204 protruding radially outward from the braking ring for engagement with a braking sleeve 205 arranged within the lower housing 103.

[0062] In the appended claims, “diverting means” is used to mean the housing assembly and the valving sleeve as described above. Also, in the appended claims, “indexing means” is intended to refer to the indexing sleeve and return spring, the threaded sleeve, the latching fingers, the spring washers, the camming sleeve, the yieldable ball seat, and the braking ring as described above.

[0063] In operation, a tool in accordance with the present invention provides for the running, hanging, and cementing of a drilling/production liner downhole in a single trip.

[0064] With reference to FIGS. 1, 2, and 2A, the tool is run into a borehole with the camming sleeve 140 and valving sleeve 141 positioned such that the long latching fingers 114 are caught on the top face of the uppermost ring at latch position 131. Further, the position is such that the short fingers 115 are positioned immediately below the uppermost ring at latch position 131. In this “open port position,” the set of sleeve flow ports 136 of valving sleeve 141 is aligned with the set of housing flow holes 126 and a flow path is established for drilling fluid to flow upward from the borehole BH into the drilling/production liner 161, from the drilling/production liner into the axial bore of the housing assembly 101, 102, 103, and from the housing assembly into the annular space between the housing assembly and the borehole via the aligned set of sleeve flow ports 136 and set of housing flow holes 126.

[0065] With reference to FIGS. 1, 2, and 2B, the drilling/production liner 161 is run into the wellbore with the preferred embodiment of the present apparatus in the open port position and thus the benefits of surge reduction are realized. However, if the drilling/production liner 161 encounters a tight hole condition within the borehole, then circulation is required to free the drilling/production liner, and the tool is moved to a closed port position. To move the tool to the closed port position, a first drop ball 127 is dropped down the drill string S, through the dart directing sleeve 109, and into the yieldable seat 110. Drilling fluid pressure is then increased above the drop ball 127 and the yieldable seat 110 to a first predetermined level, which moves the seat 110 and camming sleeve 140 from an initial axial position downward against the resistance of the spring washers 124 to a second axial position. This downward axial movement frees the radial restraint on the long latching fingers 114 while simultaneously forcing the short latching fingers 115 radially outward.

[0066] With reference to FIGS. 1, 2, and 2C, the inward radial motion of the long latching fingers 114 releases the indexing assembly and allows it and the valving sleeve 141 to move axially downward. The simultaneous outward radial motion of the short latching fingers 115 provides an external protrusion that catches on the next lower ring of the indexing sleeve 200 at latch position 132. The downward movement of the indexing assembly and attached valving sleeve 141 is arrested at latch position 132.

[0067] With reference to FIGS. 1, 2, and 2D, drilling fluid pressure above the drop ball is then increased further to a second predetermined level sufficient to pass the drop ball 127 through the yieldable seat 110. As the drilling fluid pressure increases, the indexing sleeve 200 moves the spring pusher 202, threaded sleeve 142, and valving sleeve 141 from an initial axial position downward against the resistance of the indexing sleeve return spring 201 to a second axial position. This downward axial movement actuates the braking ring 203 of the valving sleeve 141 such that the brake pad 204 (FIG. 6) engages the braking sleeve 205.

[0068] Once the yieldable seat 110 yields to an extent that permits the drop ball 127 to pass through and on down to the bottom of the borehole, the drilling fluid pressure is relieved from both the spring washers 124 and the indexing sleeve return spring 201. The spring washers 124 then reset and push the camming sleeve 140 slightly upwards into the initial axial position so that the short latching fingers 115 are free to move radially inward and the long fingers 114 are forced radially outward. Simultaneously, the indexing sleeve return spring 201 resets and moves the spring pusher 202 and the indexing sleeve 200 slightly upwards into the initial axial position while the brake pad 204 (FIG. 6) of the braking ring 203 engages the braking sleeve 205 thereby preventing the valving sleeve 141, threaded sleeve 142, and the latching fingers 114, 115 from moving upwards. This enables the radially protruding long latching fingers 114 to catch on the ring of the indexing sleeve 200 at latch position 132.

[0069] At this state, the valving sleeve 141 is in a closed port position, and circulation of drilling fluid can be established to help work the drilling/production liner 161 through the tight hole condition. In this “closed port position,” the set of housing flow holes 126 is blocked by the valving sleeve 141 and a flow path is established for drilling fluid to flow downward from the drilling rig through the drill string S, from the drill string into the axial bore of the housing assembly 101, 102, 103, from the housing assembly in the drilling/production liner 161, and from the drilling/production liner into the borehole BH to circulate around the bottom of drilling/production liner.

[0070] With reference to FIGS. 1, 3 and 3A, once circulation of the drilling fluid frees the drilling/production liner 161 from the tight hole condition, downhole running operations can continue and surge reduction can be reestablished to finish running the drilling/production to the total depth.

[0071] To move the valving sleeve 141 to the next open port position, a drop ball 129 with a diameter larger than the previous drop ball 127 is dropped down the drill string S, through the dart directing sleeve 109, and into the yieldable seat 110. Drilling fluid pressure is then increased above the drop ball 129 and the yieldable seat 110 to a first predetermined level, which moves the seat 110 and camming sleeve 140 from an initial axial position downward against the resistance of the spring washers 124 to a second axial position. This downward axial movement frees the radial restraint on the long latching fingers 114 while simultaneously forcing the short latching fingers 115 radially outward.

[0072] With reference to FIGS. 1, 3, and 3B, the inward radial motion of the long latching fingers 114 releases the indexing assembly and allows it and the valving sleeve 141 to move axially downward. The simultaneous outward radial motion of the short latching fingers 115 provides an external protrusion that catches on the next lower ring of the indexing sleeve 200 at latch position 133. The downward movement of the indexing assembly and attached valving sleeve 141 is arrested at latch position 133.

[0073] With reference to FIGS. 1, 3, and 3C, drilling fluid pressure above the drop ball is then increased further to a second predetermined level sufficient to pass the drop ball 129 through the yieldable seat 110. It should be noted that the diameters of drop balls 127 and 129 must be small enough to pass through the openings in wiper plug 162 and landing collar 160. Thus, the maximum diameters of drop balls 127 and 129 will be dictated by the type of float equipment that is used. As the drilling fluid pressure increases, the indexing sleeve 200 moves the spring pusher 202, threaded sleeve 142, and valving sleeve 141 from an initial axial position downward against the resistance of the indexing sleeve return spring 201 to a second axial position. This downward axial movement actuates the braking ring 203 of the valving sleeve 141 such that the brake pad 204 (FIG. 6) engages the braking sleeve 205.

[0074] Once the yieldable seat 110 yields to an extent that permits the drop ball 129 to pass through and on down to the bottom of the borehole, the drilling fluid pressure is relieved from both the spring washers 124 and the indexing sleeve return spring 201. The spring washers 124 then reset and push the camming sleeve 140 slightly upwards into the initial axial position so that the short latching fingers 115 are free to move radially inward and the long fingers 114 are forced radially outward. Simultaneously, the indexing sleeve return spring 201 resets and moves the spring pusher 202 and the indexing sleeve 200 slightly upwards into the initial axial position while the brake pad 204 (FIG. 6) of the braking ring 203 engages the braking sleeve 205 thereby preventing the valving sleeve 141, threaded sleeve 142, and the latching fingers 114, 115 from moving upwards. This enables the radially protruding long latching fingers 114 to catch on the ring of the indexing sleeve 200 at latch position 133.

[0075] At this state, since the tight hole condition has been alleviated, running in of the drilling/production liner 161 can resume with the benefits of surge reduction. In this “open port position,” the set of sleeve flow ports 136 of valving sleeve 141 is aligned with the set of housing flow holes 126 and a flow path is established for drilling fluid to flow from the borehole into the drilling/production liner, into the axial bore of the housing assembly and into the annular space outside the housing assembly via the aligned set of sleeve flow ports 136 and set of housing flow holes 126.

[0076] With reference to FIGS. 1, 4, and 4A, once the drilling/production liner has reached the final depth, then a final pressurization cycle must be completed in order to shift the valving sleeve 141 into the second closed port position. A final drop ball 130, with a diameter still larger than the previous drop ball 129, is dropped down into the yieldable seat 110. Drilling fluid pressure is then increased above the drop ball 130 and the yieldable seat 110 to a first predetermined level, which moves the seat 110 and camming sleeve 140 from an initial axial position downward against the resistance of the spring washers 124 to a second axial position. This downward axial movement frees the radial restraint on the long latching fingers 114 while simultaneously forcing the short latching fingers 115 radially outward.

[0077] With reference to FIGS. 1, 4, and 4B, the inward radial motion of the long latching fingers 114 releases the indexing assembly and allows it and the valving sleeve 141 to move axially downward. The simultaneous outward radial motion of the short latching fingers 115 provides an external protrusion that catches on the next lower ring of the indexing sleeve 200 at latch position 134. The downward movement of the indexing assembly and attached valving sleeve 141 is arrested at latch position 134.

[0078] With reference to FIGS. 1, 4, and 4C, drilling fluid pressure above the drop ball is then increased further to a second predetermined level sufficient to pass the drop ball 130 through the yieldable seat 110. As the drilling fluid pressure increases, the indexing sleeve 200 moves the spring pusher 202, threaded sleeve 142, and valving sleeve 141 from an initial axial position downward against the resistance of the indexing sleeve return spring 201 to a second axial position. This downward axial movement actuates the braking ring 203 of the valving sleeve 141 such that the brake pad 204 (FIG. 6) engages the braking sleeve 205.

[0079] Once the yieldable seat 110 yields to an extent that permits the drop ball 130 to pass through and on down to land in a landing collar 160 (FIG. 6) within the drilling/production liner 161, the drilling fluid pressure is relieved from both the spring washers 124 and the indexing sleeve return spring 201. The spring washers 124 then reset and push the camming sleeve 140 slightly upwards into the initial axial position so that the short latching fingers 115 are free to move radially inward and the long fingers 114 are forced radially outward. Simultaneously, the indexing sleeve return spring 201 resets and moves the spring pusher 202 and the indexing sleeve 200 slightly upwards into the initial axial position while the brake pad 204 (FIG. 6) of the braking ring 203 engages the braking sleeve 205 thereby preventing the valving sleeve 141, threaded sleeve 142, and the latching fingers 114, 115 from moving upwards. This enables the radially protruding long latching fingers 114 to catch on the ring of the indexing sleeve 200 at latch position 134.

[0080] With reference to FIGS. 1 and 5, at this state, the valving sleeve 141 is in a closed port position, the drilling/production liner is at the final depth of the wellbore, and cementing operations maybe commenced. In this final “closed port position,” the set of housing flow holes 126 is blocked by the valving sleeve 141 and a flow path is established for cement to flow downward from a cement pump into the drill string S, from the drill string into the axial bore of the housing assembly 101, 102, 103, from the housing assembly in the drilling/production liner 161, and from the drilling/production liner into the borehole BH to fix the drilling/production liner to the borehole.

[0081] With reference to FIG. 7, the drilling fluid pressure is increased inside the drilling/production liner 161 to actuate the hydraulic hanger 162 via a hanger port 162A. Drilling fluid pressure is again increased until a set of shear pins 160A, 160B fail and the drop ball 130 and the landing collar 160 fall out of drilling/production liner 161 and into borehole.

[0082] With reference to FIG. 8, once the drilling/production liner is set, cementing operations are commenced. Cement C is pumped down the drill pipe P and through the drilling/production liner 161. Once the proper quantity of cement has been pumped into the drill pipe P, a dart 164 is released from the surface into the drill pipe and drops onto the cement C. Pressurized drilling fluid is then used to push the dart 164 through the dart directing sleeve and pass the yielded seat. The dart 164 enters the drilling/production liner 161 and engages wiper plug 163.

[0083] With reference to FIG. 9, drilling fluid pressure is then increased behind the dart until plug shear pins 163A and 163B fail allowing the plug 163 to move downwardly and push the cement C through the drilling/production liner 161 and up into the annulus between the borehole and drilling/production liner until the plug 163 engages in the collar 160. Finally, the surge reduction tool is retrieved from the borehole. 

What is claimed is:
 1. Apparatus for directing flow of drilling fluid while running a tubular member through a borehole containing drilling fluid, said apparatus comprising: a housing assembly having an upper end and a lower end, said housing assembly having a set of flow holes formed therein; a valving sleeve arranged within the housing assembly having an upper end, a lower end, and two sets of flow ports formed therein at different axial locations along the valving sleeve, said valving sleeve being movable between an open port position where one set of flow ports is aligned with the set of flow holes of the housing assembly and a closed port position where the set of flow holes of the housing assembly is blocked by the valving sleeve; and indexing means for axially moving the valving sleeve from a first open port position to a first closed port position, from the first closed port position to a second open port position and from the second open port position to a second closed port position.
 2. Apparatus for use in reducing surge pressure while running a tubular member through a borehole containing drilling fluid using a drilling rig, said apparatus comprising: a drill pipe for communication between the drilling rig and the borehole, said drill pipe having an upper end operatively connected to the drilling rig and a lower end; a housing assembly having an upper end operatively connected to the lower end of the drill pipe and a lower end operatively connected to the tubular member, said housing assembly having a set of flow holes formed therein; a valving sleeve arranged within the housing assembly having an upper end, a lower end, and two sets of flow ports formed therein at different axial locations along the valving sleeve, said valving sleeve being movable between an open port position where a set of flow ports is aligned with the set of flow holes of the housing assembly and a closed port position where the set of flow holes of the housing assembly is blocked by the valving sleeve; and indexing apparatus for axially moving the valving sleeve from a first open port position to a first closed port position, from the first closed port position to a second open port position and from the second open port position to a second closed port position, said indexing apparatus comprising: (i) an indexing sleeve having an upper end, a lower end, and a plurality of rings protruding radially inward and located at different axial locations along the indexing sleeve; (ii) a threaded sleeve operatively connected to the upper end of the valving sleeve; (iii) a plurality of latching fingers each having a first end and a second end, the first end of each of said latching fingers being attached to the threaded sleeve and the second end of each of said latching fingers for engaging the rings of the indexing sleeve, some of the latching fingers having a length which is longer than the length of the remainder of the latching fingers; (iv) a set of spring washers supported by the threaded sleeve; (v) a camming sleeve having a yieldable ball seat, said camming sleeve supported by the set of spring washers and movable from a first axial position where the camming sleeve contacts the second ends of the longer latching fingers to force them into engagement with a ring of the indexing sleeve to a second axial position where the camming sleeve releases the longer latching fingers from engagement with the ring and forces the second ends of the shorter latching fingers to contact the indexing sleeve; and (vi) a return spring supporting the lower end of the indexing sleeve.
 3. The apparatus of claim 2, further comprising: a braking ring attached to the lower end of the valving sleeve, said braking ring having an outer diameter smaller than the axial bore of the housing assembly, a braking sleeve arranged within the housing assembly having an inner diameter greater than the outer diameter of the braking ring, and a brake pad attached to the braking ring and protruding radially outward for engagement with the braking sleeve.
 4. The apparatus of claim 3, further comprising: a first ball which is dropped down the drill pipe to land in the yieldable ball seat, said first ball having a predetermined diameter; means for establishing a pressure above the first ball which is sufficient to move the camming sleeve from the first axial position to the second axial position and to move the valving sleeve from the first open port position to the first closed port position; and means for establishing a second pressure above the first ball which is sufficient to force the first ball through the yieldable ball seat.
 5. The apparatus of claim 4, further comprising: a second ball which is dropped down the drill pipe to land in the yieldable ball seat, said second ball having a diameter larger than the diameter of the first ball; means for establishing a pressure above the second ball which is sufficient to move the camming sleeve from the first axial position to the second axial position and to move the valving sleeve from the first closed port position to the second open port position; and means for establishing a second pressure above the second ball which is sufficient to force the second ball through the yieldable ball seat.
 6. The apparatus of claim 5, further comprising: a third ball which is dropped down the drill pipe to land in the yieldable ball seat, said third ball having a diameter larger than the diameter of the second ball; means for establishing a pressure above the third ball which is sufficient to move the camming sleeve from the first axial position to the second axial position and to move the valving sleeve from the second open port position to the second closed port position; and means for establishing a second pressure above the third ball which is sufficient to force the third ball through the yieldable ball seat.
 7. The apparatus of claim 6, wherein the housing assembly further comprises an upper seal on the inner wall of the housing assembly located directly above the set of flow holes and a lower seal on the inner wall of the housing assembly located directly below the set of flow holes.
 8. The apparatus of claim 7, further comprising a dart directing sleeve having an upper end operatively connected with the lower end of the drill pipe and a lower end operatively connected to the yieldable ball seat, said dart directing sleeve having a smaller diameter and smoother inside wall than the drill pipe and providing a passage for a dart to travel from the drill pipe and into the yieldable ball seat.
 9. The apparatus of claim 8, wherein the return spring further comprises a spring pusher arranged between the lower end of the indexing sleeve and the return spring.
 10. The apparatus of claim 9, further comprising a hanger operatively connected between the lower end of the housing and the tubular member.
 11. A method for reducing surge pressure while running a tubular member on a drill pipe through a borehole containing drilling fluid using a drilling rig comprising the steps of: providing diverting means between the drill pipe and the tubular member to establish a flow path for drilling fluid to flow upward from the borehole into the tubular member, from the tubular member into an annular space between the drill pipe and the borehole via the diverting means; and providing indexing means to shift the diverting means to alter the flow path for a fluid to flow downward from the drilling rig to the drill pipe, from the drill pipe to the diverting means, from the diverting means to the tubular member, and from the tubular member into the borehole.
 12. The method of claim 11 wherein the fluid is drilling fluid.
 13. The method of claim 11 wherein the fluid is cement.
 14. A method for reducing surge pressure while running a tubular member on a drill pipe through a borehole containing drilling fluid using a drilling rig comprising the steps of: operatively connecting a surge pressure reduction device between the drill pipe and the tubular member, the surge pressure reduction device including diverting means, indexing means, and having a plurality of alternating open port and closed port positions; lowering the tubular member into the wellbore with the surge reduction device in a first open port position; shifting the diverting means from the first open port position to the first closed port position; shifting the diverting means from the first closed port position to the second open port position; and shifting the diverting means from the second open port position to the second closed port position.
 15. The method of claim 14, wherein each step of shifting the diverting means comprises the steps of: dropping a ball into a seat, said ball sealing with the seat; increasing drilling fluid pressure to a first predetermined level above the ball to shift the diverting means; and further increasing drilling fluid pressure to a second predetermined level above the ball to expand the seat to allow the ball to pass through the seat.
 16. Apparatus for use in directing flow of drilling fluid while running a tubular member through a borehole, said apparatus comprising: a housing assembly a set of flow holes formed therein; a valving sleeve arranged within the housing assembly having an upper end, a lower end, and two sets of flow ports formed therein at different axial locations along the valving sleeve, said valving sleeve being movable between an open port position where a set of flow ports is aligned with the set of flow holes of the housing assembly and a closed port position where the set of flow holes of the housing assembly is blocked by the valving sleeve; and indexing apparatus for axially moving the valving sleeve from a first open port position to a first closed port position, from the first closed port position to a second open port position and from the second open port position to a second closed port position, said indexing apparatus comprising: (i) an indexing sleeve having an upper end, a lower end, and a plurality of rings protruding radially inward and located at different axial locations along the indexing sleeve; (ii) a threaded sleeve operatively connected to the upper end of the valving sleeve; (iii) a plurality of latching fingers each having a first end and a second end, the first end of each of said latching fingers being attached to the threaded sleeve and the second end of each of said latching fingers for engaging the rings of the indexing sleeve, some of the latching fingers having a length which is longer than the length of the remainder of the latching fingers; (iv) a set of spring washers supported by the threaded sleeve; (v) a camming sleeve having a yieldable ball seat, said camming sleeve supported by the set of spring washers and movable from a first axial position where the camming sleeve contacts the second ends of the longer latching fingers to force them into engagement with a ring of the indexing sleeve to a second axial position where the camming sleeve releases the longer latching fingers from engagement with the ring and forces the second ends of the shorter latching fingers to contact the indexing sleeve; (vi) a return spring supporting the lower end of the indexing sleeve; and (vii) a braking device attached to the valving sleeve. 